Attachment-plug for electric circuits.



F. H. CHAPMAN & 0. E KENNEY.

ATTACHMENT PLUG FOR ELECTRIC; CIRCUITS.

APPLICATION FILED JUNE13, 1913.

Patented June 2, 1914. MEL. 2:.

UNITED STATES PATENT OFFICE.

FRANK rr. CHAPMAN Aim ownn n. KENNEY, or ronnno, OHIO.

Specification of Letters Patent.

Patented June 2, 1914,

Application filed June 13, 1913. Serial No. 773,391.

To all whom it may concern:

Be it known that we, FRANK H. CHAPMAN and OWEN E. KENNEY, citizens of the United States, and residents of Toledo, in the county of Lucas and State of Ohio, have invented a certain new and useful Attachment-Plug for Electric Circuits; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the characters of reference marked thereon, which form a part of this specification.

This invention-relates to electrical devices, and particularly to plug members of the quick connecting type of plug and socket couplings for electric circuits, but is not restricted to such use as it may be used in any connection for which it may be adapted or appropriate.

The object of our invention is the provision of an improved plug of this character which is simple and inexpensive in its construction, capable of having the parts thereof easily and quickly assembled and adapted for quick engagement with a socket member or disengagement therefrom, as desired, whereby to enhance the practicability and commercial value thereof.

The invention is fully described in the following specification, and while, in its broader aspect, it is capable of embodiment in numerous forms, a preferred embodiment thereof is illustrated in 'the accompanying drawings, in which,--

Figure 1 is a side elevation of a coupling embodying the invention with the plug member and a portion of the socket member in central longitudinal section, the section of the plug member being on the line :ca; in Fig. 3. Fig. 2 is a different side elevation thereof with portions of the coupling members broken away, and Fig. 3 is an end elevation of the plug member of the coupling.

Referring to the drawings, A designates the socket member of the coupling, which member is of customary or any suitable construction, and has the central contact part 1 and the spirally grooved or threaded lining 2 forming the other contact of the socket.

The plug member B of the coupling, in which the features of our invention reside, comprises the body part 3 and the plunger part 4:, which latter is mounted for axial reciprocatory movements in a longitudinallyextending socket 5 in one end of the body part 3. A coiled compression spring 6 is disposed in the base of the socket 5 and acts upon the plunger 4 to cause its outer end to normally project a short distance without the open end of the socket 5.

A sleeve or ferrule 7 of metal or other suitable electrical conductive material 1s fitted around the outer end portion of the body part 3, or the portion thereof which is inserted into the socket member, to provide a surfacefor contact with the lining of such member when the plug is inserted therein. For convenience of manufacture it is preferable to form the wall of the socket 5 of the plug member 3 in two parts a and b, one forming an extension of the other, the portion 7; being mounted within and forming an insulating lining for the sleeve 7 and being shorter than such sleeve to adapt the inner end of the sleeve to project therefrom, as shown. The inner or projecting endof the sleeve is rolled or otherwise suitably formed with a short thread 8, which is intended to thread over the free end of the portion a of the plug and draw the portions a and Z) firmly together in endwisc abutment. The

parts of the body member 3 having been assembled in this manner, the threaded end of the sleeve 7 and the portion a of the-plug part are secured against disengagement by a pin 9, "or in any other suitable manner. The thread 8 in addition to serving as a uniting means for the parts a and Z) of the body part 3 of the plug, also cooperates with the outer end portion of the threaded lining 2 of the socket member to retain the members of a coupling in engagement.

The circuit wires 10 and 11 extend into the socket 5 of the plug through an opening 12 in the closed end of the body part 3, and the wire 10, in the present instance, extends through a longitudinally disposed opening or passage 13 in the plunger and hasits free end attached to a center contact 14 at the outer end of the plunger by a binding screw 15, or in any other suitable manner. The other circuit Wire 11 extends into a longitudinally disposed recess 16 in one side of the plunger and is secured by a binding screw 17 or in any other suitable manner to a conductor strip 18 which projects inwardl from the sleeve 7, as shown in Fig. 1. The sleeve .7 is preferably slit at its outer end, and the tongue or strip 18, which is provided thereby is bent inwardly through a registering opening 19 in the part b of the body portion of the plug member and into the recess 16 of the plunger.

e In order to limit the relative outv-ard movements of the plug parts 3 and 4 under the influence of the spring 6 a spring finger 20 is mounted within a longitudinally disposed recess 21 in one side of the plunger it within the socket 5 and has its free end portion extending outward-into a'registering longitudinally extending recess 22 in the Wall of the socket 5 in position to have contact with the inturned outer end flange 23 of the sleeve 7. vided in the sleeve 7 in register with the free end portion of the spring finger 20 to permit the insertion of a pointed tool therethrough into contact with the finger end to effect a compression of the finger within the recess 22 to a suflicient extent to permit it to pass the stop flange 23 of the ferrule upon an outward movement of the plunger, thus enabling the plug parts 3 and 4 to be easily removed one from the other.

The provisionof a thread'8 at tlid inner end portion of the sleeve 7 in position to engage the outer end portion of the thread of the'socket lining 2 is an important feature of our plug when considered in connection with the yieldingly mounted plunger 4 carrying the center contact 14 of the plug. lVith this construction it is only necessary for a person in making an electrical coupling to insert the plug into the socket member a suflicient extent to eficct a contact between the center contact 1 and 14- of such members and then to give the plug a slight turn in clockwise direction to effect a looking engagement of the short thread section 8 of the plug with the thread of the socket lining 2. The turning of the body portion 3 of the plug into the socket member in threaded engagement therewith causes a compression of the plunger or center contact carrying part 4 ofthe plug within the body member and insures a close and etficient contact between the parts 1 and let.

It is found in practice that our present plug is highly efficient in its operation and requires only a .very slight relative turning of the plug and socket members, for instance, about one-quarter of a turn, to effect an engagement of the members and a close electrical contact between the parts 1 and let. The sleeve 7 being in binding con- An aperture 24 is pro-.

l l l tact with the threaded lining 2 forms a close electrical contact therebetween. V

lVe wish it understood that our invention is not limited to any specific construction or arrangement of the parts except in so far as such limitations are specified in the claims.

Having thus described our invention, what we claim as new, and desire to secure by Letters Patent, is,

1. In a coupling of the class described, in combination, a socket member having cen ter and outerscrew shell contacts, a plug member having center and outer screw shell contacts, the distance from the center contact of the plug member to the threaded portion of the outer screw shell contact thereof being substantially equal to or greater than the distance from the center contact of thesocket member to the outer end or the screw threaded portion of the outer screw shell contact of the socket memher, one center contact being movable relative to its corresponding screw shell contact,

whereby locking engagement of the members will be secured-by relative'jl-ongitudinal and comparatively small rotary vmovements thereof when the center contacts are in contact.

2. In a coupling of the class described, in combination, a socket member having center and outer screw shell contacts, a plug member having an outer screw shell contact and a center contact yieldingly compressible relative thereto, the distance from the center contact of the plug member, when extended,-tothe threaded portion or the outer screw shell contact thereof being substantially equal to the distance from the center contact of the socket membcri to the outer end of the screw threaded portion of the outer screw shell contact of the socket member, wh-crcbythe threaded portions of the members are permitted to turn into engagement when the center contacts are in contact and during a compression of the yielding center contact.

In testimony whereof,- we have hereunto signed our names to this specification in 105 the presence of two subscribing witnesses. 

